The present invention relates to a transformer, and particularly to a transformer having magnetic shields in a tank.
In a transformer configured using an iron core including an iron core leg part and an iron core yoke part and a winding wound around the iron core leg part, magnetic flux leaked from the winding enters a tank or an iron core fastening metal fitting for fixing the iron core, and eddy current loss is generated.
Recently, the transformer is downsized to reduce the manufacturing cost, and the density of leaked magnetic flux tends to be increased. In order to reduce the loss by the leaked magnetic flux, it is desirable to reduce the loss in the tank or the iron core fastening metal fitting.
Japanese Unexamined Patent Application Publication No. Hei10 (1998)-116741 is one of the background techniques of the technical field. The publication describes a structure in which in a magnetic shield that is arranged on the surface of a tank and obtained by laminating silicon steel sheets, a magnetic shield part obtained by laminating silicon steel sheets is provided in the rear of the surface opposite to a winding.
Further, Japanese Unexamined Patent Application Publication No. Hei9(1997)-293622 is also one of the background techniques. The publication describes a structure in which a two-layer magnetic shield formed using a magnetic shield obtained by laminating silicon steel sheets and a magnetic shield surrounded by sound absorbing materials is attached to a tank.